<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="../react18/react.development.js"></script>
  <script src="../react18/react-dom.development.js"></script>
  <script src="../react18/babel.min.js"></script>
</head>

<body>
  <div id="app"></div>
  <script type="text/babel">

    class App extends React.Component{
      state = {
        count:0,
        content:"类式组件"
      }

      render(){
        console.log("----render----");
        const {count} = this.state;
        return (
          <div>
            <button onClick={this.handle} >+</button>
            <p>{count}</p>
          </div>
        )
      }

      //事件函数
      handle = () => {
        //组件实例上有一个setState方法,接受一个对象,会把接受的对象和原有的state对象进行合并,并重新渲染
        //千万不要直接修改state,而是使用setState
        this.setState({count:1,isHot:true});
        this.setState({isXiake:false});

        //setState可能是异步的(处于性能考虑,会等待以下,把多个setState合并成一次更新,比如上边的案例,调用了两次setState,但是rende只执行了依次)
        console.log("this.state.count",this.state.count);//0
      }
    }

    const root = ReactDOM.createRoot(document.getElementById('app'));
    root.render(<App/>)




  </script>
</body>

</html>